Do you find them helpful at all?
At the moment, I am spending a lot of time on the game - so I often just check on the game which places have been invaded + which harvesters are full. But when I am in class I don't always get a chance to go onto the Year 0 client, so its helpful to quickly check whats happening.

Do they cause an immediate reaction? (for example, if you get a message about an invasion, do you do something about it as soon as you get it, or do you just carry on the way you were doing?)
Yes, if I have units left in stock I send something to break up the invasion party as soon as possible. If all of my units are deployed, I tend to complete the current battle and then send in a defence. I often also ask friends to come and help me as they have no traveling time (30 seconds for them compared to 10 - 60 mins for me).

Are the emails a helpful reminder to return to the game after you've been absent for a while?
I haven't yet been absent from the game since starting to play it, I must say I am quite addicted at the moment! I don't think my feedback on this area would be valuable.

Are you receiving too many messages and emails? Do they feel like spam?
This is something that really gets on my nerves. My inbox at the moment feels like my e-mail account I had when I was 9 years old, chock-a-block with spam. I think that maybe e-mail updates should be sent out only every 3 hours and this should give a recap of what has happened instead of every tiny detail being given in separate e-mails. If nothing has happened then the e-mail is not sent. We should also have an option to disable all or certain reminders.

Are you not receiving enough?
As stated above quite the contrary, I only don't receive e-mails if I am logged in and active in the game which is fair enough.

Would you like more information and if so - would you like anything specific?
I think the information that is sent is adequate, it informs me if my harvesters are full, who is invading me and other things like if someone is helping me or if someone wants help.

Any other comments about messages and emails in general?
The only thing that needs addressing is the bulk of emails sent to you. Otherwise the Intel system is good.

I do, primarily the ones telling me that I'm under attack, and my harvesters are full - but I'm generally online anyway. As I also have emails rigged to send to my phone, it reminds me to check more regularly.

Do they cause an immediate reaction? (for example, if you get a message about an invasion, do you do something about it as soon as you get it, or do you just carry on the way you were doing?)

Generally, yes - but this is only when I actually see my emails, I check Year 0 a lot more commonly than I do my emails, so the only way they cause an immediate reaction is when they're sent directly to my phone. If it's telling me that my harvester is full, I'll unload it ASAP - but if I'm being invaded I check where the territory is, how far away it is and make a decision from there.

Are the emails a helpful reminder to return to the game after you've been absent for a while?

How does one become absent? I need to know this dark magic...

Are you receiving too many messages and emails? Do they feel like spam?

Most definitely, uh, prior to Year 0 I maintained a clean inbox - with the quantity of emails I get concerning Year 0 it's barely possible anymore. I reckon what Gareth said regarding being able to disable all/certain reminders is definitely a very good idea and this would help me control the flow of emails immensely. The ones I find most useful would be "-- has invaded --" and "-- harvester is full!", others such as friends requesting help, people being repulsed are not quite as useful (in my opinion).

Are you not receiving enough?

^

Would you like more information and if so - would you like anything specific?

I think the amount of reminders we get concerning current events are enough, and I can't really think of anything else that would be worth an email, but I will edit my post if I think of one.

Any other comments about messages and emails in general?

I think overall the system is pretty good, the only "negative" aspect is the quantity of emails.